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    <title>Document</title>
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<body>
    <script>
        // typeof 数值
        // typeof 变量名 
        // typeof(数值)
        // typeof(变量名)

        // console.log(typeof 100);
        // console.log(typeof 100.5);
        // console.log(typeof 10e5);
        // console.log(typeof 0xabc);
        // console.log(typeof NaN);
        // console.log(typeof Infinity);
        // console.log(typeof -Infinity);


        // console.log(typeof 'adf ');
        // console.log(typeof "adf ");
        // console.log(typeof "adf ");



        /* 
        
        number
        number
        number
        number
        number
        number
        number
        string
        string
        string
        boolean
        boolean
        object   
        undefined
        */


        // console.log(typeof true);
        // console.log(typeof false);



        // console.log(typeof null);

        // console.log(typeof undefined);


        console.log(typeof typeof 123);// string 
        // 1 typeof 123  => number  是个单词  也就是字符串
        // 1 typeof 'number' = > string 


        console.log(typeof(123));// number 
        console.log(typeof(typeof(123))); // string












    </script>
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